Harlequin fish
(Othos dentex)

The harlequin fish (Othos dentex) is a species of marine ray-finned fish in the subfamily Anthiinae, part of the family Serranidae, the groupers and sea basses. It is the only member of the genus Othos. It is also known commonly as the Chinese lantern, harlequin cod, harlequin rock cod and tiger cod. This species is found in the Eastern Indian Ocean and is endemic to Australian waters, in subtropical areas typically rocky reefs.

Description
The harlequin fish is one of the largest serranids in the Western and Southern Australian water, is a diurnal forager that has a long life-cycle, and has a small home range and strong site fidelity. It is likely to be harmed by localized anthropogenic changes and by recreational fishing, though their fishing along the coast is low.

Harlequin fish vary greatly in size but reach a maximum length of 75 cm to 86 cm and weight of 6 kg. it has a heterogeneous color pattern that varies from individual to individual, which blends with the colors and surrounding coralline algea and encrusting sponges in the reef, providing a camouflage for them. The color variation, between individuals, is due to the large blotches which range from yellow to green, that are located posterior to the pectoral fin on the lower half of the body. While all individuals have longitudinal blue flecks on the dorsal surface of the body, as males become mature these flecks become more prominent, and their spots change from yellow to green and finally, once they reach full maturity, to blue.

During spawning season, the color of blotches in males intensify, peaking at intensity during the midpoint of the season, which plays a role in courtship.[4] This color change also suggests a change in their androgen levels.

O. dentex has independently movable eyes that protrude on top of its head, and a large sized mouth.